When a boat or small ship is moored at a dock or the like, electrical power is commonly supplied from a shore or dockside power center which includes at least two electrical receptacles into which cables from the vessel can be inserted. Such a power center commonly has two or more identical receptacles each supplying 120 volts AC. If all of the equipment aboard the vessel is designed to operate at that same voltage, there is no problem. However, if equipment such as blower motors, pumps or the like are wired for 208-240 volt power, that equipment may either not operate at all or operate at a low speed and overheat because of improper voltage. Thus, it is common for a boat owner to make or buy a "Y" adapter with two male 120 volt plugs connected to a single 125/250 volt connector having female contacts. The 125 volt plugs are then inserted into the two receptacles on the dockside power center and the single 125/250 volt connector is plugged into the marine vessel ship-to-shore cable set as an input to the receptacle on the vessel. The electrical wiring for the vessel is connected to this receptacle.
While this solution is an improvement, it is possible for an unwary user to disconnect one of the male plugs and be exposed to line voltage on the contact blades of the male plug.